The film, a sequel to 2017's Spider-Man: Homecoming and 2019's Spider-Man: Far From Home, will reunite Tom Holland's Peter Parker with Zendaya as MJ, Marisa Tomei as Aunt May, Jacob Batalon as Ned and Tony Revolori as Eugene. In addition, Benedict Cumberbatch will appear as Doctor Strange, reprising his role from several previous Marvel movies.
Where the casting gets interesting is the villains: Jamie Foxx will appear as Max Dillon, aka Electro. He last played that role in The Amazing Spider-Man 2 (2014), but that was in a different continuity. Today it was confirmed that Alfred Molina will be reprising his role a Otto Octavius, aka Doctor Octopus, from Spider-Man 2 (2004), which was set in a yet another continuity.
According to Collider, the film will go further and will also incorporate appearances by Andrew Garfield, who played Spider-Man/Peter Parker in The Amazing Spider-Man (2012) and its sequel; and Kirsten Dunst as MJ from the Sam Raimi trilogy: Spider-Man (2002), Spider-Man 2 (2004) and Spider-Man 3 (2007). They also claim that Tobey Maguire is in talks to reprise his role as Peter Parker/Spider-Man from the Raimi trilogy, and Emma Stone is being considered for a return as Gwen Stacey from the Garfield duology.
To be clear, it's unknown if this latter casting is for a barrage of cameos or for meatier roles in the movie. It's also unclear if CG or effects will be used to make the returning actors appear the same way they did in their films (in Maguire and Dunst's case, almost twenty years ago, somehow) or if they will be playing older versions of their characters in a similar vein to the animated movie Into the Spider-Verse (2018), which was surprise hit with its story of interdimensional Peter Parkers teaming up with Miles Morales and a number of other variations on the Spider-Man archetype to fight Kingpin.
The film is currently scheduled to open on 17 December 2021. Into the Spider-Verse 2 is also in production and currently targeting an October 2022 release date.